In the known orthoses of this type, the two splints are oriented flush with one another and are designed to be able to pivot relative to one another about a common pivot axis, the pivot hinge part having to be provided with a means of limiting the relative pivoting movement. In an ankle joint orthosis, a foot-elevating function can be effected by means of the foot part being pressed by a spring into a starting position which, through the pressure applied when putting down the heel of the foot part (first joint part) counter to the spring force, is abandoned in order to thus permit a certain heel-to-toe rolling movement during walking.
The foot part and the below-knee part (second joint part) are generally designed as shells made of plastic in order to engage in a supportive manner in a U-shape around the foot and the lower leg. For stable connection of the foot splint and of the foot part, a certain length is required which, in the known construction, has to be provided below the pivot hinge part. In addition, a certain length is needed for the anchoring of the foot splint in the pivot hinge part. For this reason, a certain minimum structural height is needed for the foot part up to the pivot hinge axis. For kinematic and esthetic reasons, however, it would be advantageous to permit a design of the foot part with a lower height.
DE 563 009 discloses a joint orthosis of the type mentioned at the outset, in which a sole part engaging under the foot of the prosthesis wearer is connected to an upwardly extending lateral splint consisting of two parts which are connected to one another by a hinge. The hinge part comprises, on both sides, the upper end of the lower splint part and the lower end of the upper splint part, the lower end of the upper splint part being mounted pivotably on the hinge part. The upper end of the lower splint part extends upward beyond the hinge part so as to limit the pivoting movement of the upper joint part toward the front, in other words to define the extended position of the lateral splint. The hinge part is arranged in this case at a substantial distance from the sole part, so as to lie safely above the upper edge of the shoe during use. The limit stop formed by the upper end of the lower splint is adjustable by means of leather or metal tongues of greater or lesser thickness or, if appropriate, a displaceable wedge being inserted between the splints.
GB 2 235 245 A discloses a polycentric knee joint consisting of two pivot hinges which, in the extended state, are flush with one another and are formed in a hinge housing. The hinge housing delimits the maximum extension of the joint splints with the aid of a T-shaped insert between the side walls of the hinge housing. By means of different inserts, it is possible to form different extension angles which can deviate to a greater or lesser extent from 180°.